diff --git a/Makefile.include b/Makefile.include
index 4fe43c265..1d06acd23 100644
--- a/Makefile.include
+++ b/Makefile.include
@@ -167,14 +167,12 @@ MAKE_NET ?= MAKE_NET_IPV6
 
 ifeq ($(MAKE_NET),MAKE_NET_NULLNET)
   CFLAGS += -DNETSTACK_CONF_WITH_NULLNET=1
+  MODULES += os/net/nullnet
 endif
 
 ifeq ($(MAKE_NET),MAKE_NET_IPV6)
   CFLAGS += -DNETSTACK_CONF_WITH_IPV6=1
   MODULES += os/net/ipv6
-else
-  CFLAGS += -DNETSTACK_CONF_WITH_NULLNET=1
-  MODULES += os/net/nullnet
 endif
 
 ifeq ($(MAKE_NET),MAKE_NET_OTHER)